Interim Results (Unaudited) - Summary of Results of Operations for Quarterly Periods (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 56,582	$ 57,052	$ 58,141	$ 59,750	$ 58,119	$ 56,910	$ 56,081	$ 56,109	$ 231,525	$ 227,219	$ 226,299
Net Income	15,041	15,328	16,750	17,077	15,509	16,702	15,902	14,946
Net income attributable to Saul Centers, Inc.	12,818	12,226	13,232	13,447	12,269	13,155	12,543	12,587	51,723	50,554	48,257
Net income available to common stockholders	$ 6,464	$ 9,016	$ 10,279	$ 10,494	$ 9,316	$ 10,202	$ 9,590	$ 6,856	$ 36,253	$ 35,964	$ 35,882
Net income available to common stockholders per diluted share (in usd per share)	$ 0.27	$ 0.39	$ 0.45	$ 0.46	$ 0.41	$ 0.45	$ 0.43	$ 0.31	$ 1.57	$ 1.60	$ 1.63